Climate and monthly weather forecastGrinnell, IA
Climate and monthly weather forecast
Weather in January
January, like December, is a freezing cold winter month in Grinnell, Iowa, with an average temperature varying between 13.8°F (-10.1°C) and 27°F (-2.8°C). Grinnell's coldest weather arrives in January, when temperatures average a high of 27°F (-2.8°C) and a low of 13.8°F (-10.1°C). Weather in January »Weather in February
The last month of the winter, February, is another freezing cold month in Grinnell, Iowa, with an average temperature ranging between min 17.4°F (-8.1°C) and max 31.1°F (-0.5°C). The onset of February brings an average high-temperature of a still freezing cold 31.1°F (-0.5°C), nearly matching the January temperature. Weather in February »Weather in March
The first month of the spring, March, is a frosty month in Grinnell, Iowa, with an average temperature varying between 45.7°F (7.6°C) and 31.3°F (-0.4°C). As February transitions into March, a clear upsurge in temperatures is observed, with average highs advancing from a freezing cold 31.1°F (-0.5°C) to a frosty 45.7°F (7.6°C). Weather in March »Weather in April
April in Grinnell, Iowa, is a mild spring month, with an average temperature varying between 41.9°F (5.5°C) and 58.5°F (14.7°C). As April begins, there is an increase in the average high-temperature, moving from a frosty 45.7°F (7.6°C) in March to a refreshing 58.5°F (14.7°C). Weather in April »Weather in May
The last month of the spring, May, is a pleasant month in Grinnell, Iowa, with an average temperature ranging between min 52.3°F (11.3°C) and max 69.3°F (20.7°C). As May arrives, Grinnell's weather shows an increase in high-temperatures, moving from April's refreshing 58.5°F (14.7°C) to an agreeable 69.3°F (20.7°C). Weather in May »Weather in June
The first month of the summer, June, is a warm month in Grinnell, Iowa, with temperature in the range of an average low of 62.4°F (16.9°C) and an average high of 78.4°F (25.8°C). The start of June is characterized by an increase in the average high-temperature, transitioning from a pleasant 69.3°F (20.7°C) in May to a moderately hot 78.4°F (25.8°C). Weather in June »Weather in July
July, the same as June, is another warm summer month in Grinnell, Iowa, with an average temperature varying between 64.8°F (18.2°C) and 81.1°F (27.3°C). In Grinnell, the month of July registers the highest temperatures, averaging 81.1°F (27.3°C) at the peak and 64.8°F (18.2°C) at the lowest. The heat index value for July is estimated at a tropical 87.8°F (31°C). Weather in July »Weather in August
August, the last month of the summer in Grinnell, is another warm month, with an average temperature varying between 80.2°F (26.8°C) and 62.2°F (16.8°C). Welcoming August, Grinnell notes an average high-temperature of a still warm 80.2°F (26.8°C), nearly consistent with July's 81.1°F (27.3°C). Weather in August »Weather in September
The first month of the autumn, September, is still a warm month in Grinnell, Iowa, with an average temperature fluctuating between 74.7°F (23.7°C) and 55.8°F (13.2°C). During the shift to September, a minor reduction in average high-temperature is observed, shifting from 80.2°F (26.8°C) in August to a still moderately hot 74.7°F (23.7°C). Weather in September »Weather in October
October, like September, is a moderate autumn month in Grinnell, Iowa, with an average temperature varying between 44.4°F (6.9°C) and 59.9°F (15.5°C). With the transition into October, Grinnell experiences a significant decrease in average high-temperatures, moving down from a moderately hot 74.7°F (23.7°C) in September to a mild 59.9°F (15.5°C). Weather in October »Weather in November
November, the last month of the autumn in Grinnell, is another chilly month, with an average temperature varying between 32.5°F (0.3°C) and 46.2°F (7.9°C). Onset of November witnesses a reduction in the average high-temperature, falling from a moderate 59.9°F (15.5°C) in October to a chilly 46.2°F (7.9°C). Weather in November »Weather in December
The first month of the winter, December, is also an icy month in Grinnell, Iowa, with an average temperature fluctuating between 33.1°F (0.6°C) and 22.1°F (-5.5°C). December shows a mild decline in the average high-temperature, falling from November's frosty 46.2°F (7.9°C) to a wintry 33.1°F (0.6°C). Weather in December »Updated: Feb 12, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
The coldest period in Grinnell is January, when temperatures fluctuate between an average high of 27°F (-2.8°C) and a low of 13.8°F (-10.1°C).
January is the most humid month, with an average relative humidity of 84%.
The month with the least rainfall is January, when the rain falls for 4.3 days and typically collects 0.47" (12mm) of precipitation.
In Grinnell, during the entire year, the rain falls for 117.5 days and collects up to 13.03" (331mm) of precipitation.
January through May, October through December are months with snowfall in Grinnell.
January is the month with the most snowfall in Grinnell. Snow falls for 8.1 days and accumulates 1.81" (46mm) of snow.
Throughout the year, in Grinnell, Iowa, there are 30.7 snowfall days, and 6.06" (154mm) of snow is accumulated.
With an average of 4.1h of sunshine, January has the least sunshine of the year in Grinnell.
January is the month with the lowest UV index, with an average maximum UV index of 1.
On Sunday, March 10. 2024, at 2:00 am, Daylight Saving Time starts in Grinnell, Iowa, and the time zone changes from CST to CDT. Daylight Saving Time ends Sunday, November 3. 2024, at 2:00 am, and the time zone reverts from CDT to CST.
The months with the most rainfall in Grinnell are May and June, with an average 1.97" (50mm) of precipitation.
In Grinnell, Iowa, snow does not fall in June through September.
The month with the longest days in Grinnell is June, with an average of 15h and 12min of daylight.
The months with the highest UV index are June and July, with an average maximum UV index of 6.
July stands out as Grinnell's warmest month, with an average high-temperature of 81.1°F (27.3°C) and a low-temperature of 64.8°F (18.2°C).
The month with the most sunshine is July, with an average of 10.2h of sunshine.
With an average relative humidity of 71%, October is the least humid month in Grinnell, Iowa.
With an average of 9h and 12min of daylight, December has the shortest days of the year in Grinnell, Iowa.
Average temperature
Grinnell, IA
The warmest month (with the highest average high temperature) is July (81.1°F).
The month with the lowest average high temperature is January (27°F).
The month with the highest average low temperature is July (64.8°F).
The coldest month (with the lowest average low temperature) is January (13.8°F).
Average pressure
Grinnell, IA
- Average pressure in January:
30.15"Hg - Average pressure in February:
30.14"Hg - Average pressure in March:
30.07"Hg - Average pressure in April:
29.93"Hg - Average pressure in May:
29.93"Hg - Average pressure in June:
29.89"Hg
- Average pressure in July:
29.96"Hg - Average pressure in August:
29.97"Hg - Average pressure in September:
30.02"Hg - Average pressure in October:
30.01"Hg - Average pressure in November:
30.09"Hg - Average pressure in December:
30.11"Hg
The month with the highest atmospheric pressure is January (30.15"Hg).
The month with the lowest atmospheric pressure is June (29.89"Hg).
Average wind speed
Grinnell, IA
- Average wind speed in January:
10.6mph - Average wind speed in February:
10.5mph - Average wind speed in March:
10.5mph - Average wind speed in April:
10.7mph - Average wind speed in May:
9.1mph - Average wind speed in June:
8mph
- Average wind speed in July:
7.1mph - Average wind speed in August:
7mph - Average wind speed in September:
8.1mph - Average wind speed in October:
9.6mph - Average wind speed in November:
10.4mph - Average wind speed in December:
10.1mph
The windiest month (with the highest average wind speed) is April (10.7mph).
The calmest month (with the lowest average wind speed) is August (7mph).
Average humidity
Grinnell, IA
The month with the highest relative humidity is January (84%).
The month with the lowest relative humidity is October (71%).
Average rainfall
Grinnell, IA
- Average rainfall in January:
0.47" - Average rainfall in February:
0.51" - Average rainfall in March:
0.87" - Average rainfall in April:
1.3" - Average rainfall in May:
1.97" - Average rainfall in June:
1.97"
- Average rainfall in July:
1.5" - Average rainfall in August:
1.02" - Average rainfall in September:
1.26" - Average rainfall in October:
0.94" - Average rainfall in November:
0.71" - Average rainfall in December:
0.51"
The wettest months (with the highest rainfall) are May and June (1.97").
The driest month (with the least rainfall) is January (0.47").
Average rainfall days
Grinnell, IA
- Average rainfall days in January:
4.3 days - Average rainfall days in February:
4.1 days - Average rainfall days in March:
9.6 days - Average rainfall days in April:
12 days - Average rainfall days in May:
14.6 days - Average rainfall days in June:
15.1 days
- Average rainfall days in July:
13.3 days - Average rainfall days in August:
11.9 days - Average rainfall days in September:
10.6 days - Average rainfall days in October:
9.1 days - Average rainfall days in November:
7.2 days - Average rainfall days in December:
5.7 days
The month with the highest number of rainy days is June (15.1 days).
The month with the least rainy days is February (4.1 days).
Average snowfall
Grinnell, IA
- Average snowfall in January:
1.81" - Average snowfall in February:
1.77" - Average snowfall in March:
0.67" - Average snowfall in April:
0.31" - Average snowfall in May:
0.2" - Average snowfall in June:
0"
The month with the highest snowfall is January (1.81").
The months with the least snowfall are June, July, August and September (0").
Average snowfall days
Grinnell, IA
- Average snowfall days in January:
8.1 days - Average snowfall days in February:
7.8 days - Average snowfall days in March:
4 days - Average snowfall days in April:
1.3 days - Average snowfall days in May:
0.2 days - Average snowfall days in June:
0 days
- Average snowfall days in July:
0 days - Average snowfall days in August:
0 days - Average snowfall days in September:
0 days - Average snowfall days in October:
0.5 days - Average snowfall days in November:
1.9 days - Average snowfall days in December:
6.9 days
The month with the highest number of snowfall days is January (8.1 days).
The months with the least snowfall days are June, July, August and September (0 days).
Average daylight / Average sunshine
Grinnell, IA
- Average daylight in January:
9h and 36min - Average daylight in February:
10h and 36min - Average daylight in March:
12h and 0min - Average daylight in April:
13h and 24min - Average daylight in May:
14h and 36min - Average daylight in June:
15h and 12min
- Average daylight in July:
14h and 54min - Average daylight in August:
13h and 48min - Average daylight in September:
12h and 30min - Average daylight in October:
11h and 6min - Average daylight in November:
9h and 48min - Average daylight in December:
9h and 12min
The month with the longest days is June (Average daylight: 15h and 12min).
The month with the shortest days is December (Average daylight: 9h and 12min).
- Average sunshine in January:
4h and 6min - Average sunshine in February:
4h and 18min - Average sunshine in March:
6h and 18min - Average sunshine in April:
7h and 54min - Average sunshine in May:
8h and 42min - Average sunshine in June:
9h and 42min
- Average sunshine in July:
10h and 12min - Average sunshine in August:
9h and 54min - Average sunshine in September:
9h and 30min - Average sunshine in October:
5h and 30min - Average sunshine in November:
5h and 30min - Average sunshine in December:
4h and 36min
The month with the most sunshine is July (Average sunshine: 10h and 12min).
The month with the least sunshine is January (Average sunshine: 4h and 6min).
Average sunshine days
Grinnell, IA
- Average sunshine days in January:
21.1 days - Average sunshine days in February:
17.8 days - Average sunshine days in March:
17.4 days - Average sunshine days in April:
14.9 days - Average sunshine days in May:
13.5 days - Average sunshine days in June:
11.5 days
- Average sunshine days in July:
12.6 days - Average sunshine days in August:
16.4 days - Average sunshine days in September:
17.9 days - Average sunshine days in October:
19.8 days - Average sunshine days in November:
20.1 days - Average sunshine days in December:
20.9 days
The month with the most sunshine days is January (21.1 days).
The month with the least sunshine days is June (11.5 days).
Average UV index
Grinnell, IA
The months with the highest UV index are June and July (UV index 6).
The month with the lowest UV index is January (UV index 1).
Average cloud cover
Grinnell, IA
The month with the most cloud cover is January (Cloud cover 55).
The month with the least cloud cover is September (Cloud cover 29).
Average visibility
Grinnell, IA
The months with the highest visibility are January, February, March, April, May, June, September, October, November and December (6mi).
The months with the lowest visibility are July and August (5mi).
